Hydrogen Enhanced-Cracking of High-Strength Steel Welded Joints

• Autorzy: Ćwiek J.
• Języki publikacji: EN

Abstrakty

EN

Aim of this paper is evaluation of susceptibility of high-strength steel welded joints to hydrogen degradation and establishing of applicable mechanism of their hydrogen-enhanced cracking. High-strength quenched and tempered steel grade S690Q and its welded joints have been used. Susceptibility to hydrogen degradation of steel and welded joints has been evaluated using monotonically increasing load. Slow strain rate test (SSRT) was carried out on round smooth specimens in air, and seawater under cathodic polarization. Elongation and reduction in area were choosen as measures of susceptibility to hydrogen embrittlement. Fractographic examinations with the use of scanning electron microscope (SEM) were performed to establish suitable mechanism of hydrogen-enhanced cracking of the welded joints. Tested high-strength steel and its welded joints are susceptible to hydrogen embrittlement when evaluated with the use of SSRT. The loss of plasticity is higher for welded joints then for the base metal. There is no possibility to perform direct observations of exact mechanism of hydrogen-assisted cracking so far. On the base of mechanical tests and fractographic observations it is likely to deduce which of nowadays models of hydrogen degradation and cracking is the most viable. Tested steel and its welded joints could be safely utilized in marine constructions under cathodic protection provided that overprotection does not take place. Hydrogen-enhanced localized plasticity (HELP) model is more applicable mechanism of hydrogen degradation than other for high-strength welded joints in seawater environment.

Słowa kluczowe

EN

crack resistance; high-strength steel; welded joint; hydrogen degradation

• Wydawca: Politechnika Gdańska
• Czasopismo: Advances in Materials Science
• Rocznik: 2008
• Tom: Vol. 8, nr 4(18)
• Strony: 4--13
• Opis fizyczny: Bibliogr. 15 poz., rys., fot., tab.

Twórcy

autor

Ćwiek J.

• Gdańsk University of Technology, Faculty of Mechanical Engineering, Poland

Bibliografia

• 1. J. Ćwiek, High strength weldable steels, Mechanical Review, 9 (1996) 9-15 (in Polish).
• 2. L. Coudreuse, C. Renaudin, P. Bocquet, L. Cadiou, Evaluation of hydrogen assisted cracking resistance of high strength jack-up steels, Marine Structures 10 (1997) 85-106.
• 3. J. V. Sharp, J. Billingham, M. J. Robinson, The risk management of high-strength steels in jack-ups in seawater, Marine Structures 14 (2001) 537-551.
• 4. Offshore Technology Report – OTO 1999 056, A review of the effects of microstructure on the hydrogen embrittlement of high strength offshore steels. Health and Safety Executive, 1999.
• 5. P. F. Timmins, Solutions to hydrogen attack in steels, AMS Int., 1997.
• 6. A. Zieliński, Hydrogen degradation of nonferrous metals and alloys, Gdańsk Scientific Society, Gdańsk, 1999 (in Polish).
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• 8. H. K. Birnbaum, I. M. Robertson, P. Sofronis, D. Teter, Mechanisms of hydrogen related fracture. A review, Proc. 2nd Int. Conf. Corrosion Deformation Interaction, The Institute of Materials, London (1997) 172-195.
• 9. J. P. Hirth, Effects of hydrogen on the properties of iron and steel, Metallurgical Transactions A, 11A (1980) 861-890.
• 10. S.P. Lynch, A commentary on mechanisms of environmentally assisted cracking, Second Int. Conf. on „Corrosion-Deformation Interactions CDI’96” Nice, France, The Institute of Materials (1996) 206-219.
• 11. PN-EN 10137-2:2000 Plates and wide flats made of high yield strength structural steels in the quenched and tempered or precipitation hardened conditions – Delivery conditions for quenched and tempered steels.
• 12. PN-EN 10002-1:2004 Metallic materials – Tensile testing – Part 1 – Method of test at ambient temperature.
• 13. PN-EN ISO 7539-7 Corrosion of metals and alloys – Stress corrosion testing – Part 7: Slow strain rate testing.
• 14. PN-EN ISO 7539-7 Corrosion of metals and alloys – Stress corrosion testing – Part 4: Preparation and use of uniaxially loaded tension specimens.
• 15. PN-66/C-06502. Substitute seawater.